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Friday, August 26, 2011

Do you get annoyed, each time you start a soldering task, and find the solder-tip-cleaning-sponge has dried out to a Crispy Critter?

Yes, I know it's an old Soldering Iron,but, it works.

And, that Critter, does not want to readily absorb water?

What a pain!

There may be a Solution.

For the last week or so, I have been experimenting with Tin Plating Methods for my Homebrew PCB Projects. For this, I have read and learned a lot of chemistry. In the Electroplating Industry, Polyethylene Glycol (PEG) is used to; slow the growth of Tin Whiskers, and to keep the new Tin Plated surface smooth and shiny. The PEG shields the sharp crystal growth points, while allowing other non-pointed areas to attract more Tin. The results is a much better, even Tin plated deposit.

I did not have PEG to use for my Homebrew plating experiments, but I had a similar material Propylene Glycol (PG) which has similar properties. I have some PEG on order, but for now PG seems to work.

But then, "While working in my Lab, late one night . . . ", I discovered a paper towel that had been previously used to wipe-up spilled PG, it had not dried! It was still moist and soft.

I remembered from my previous research, PG and PEG are used in many products in industry like; food, medical, and toothpaste. PEG and PG are used to attract and/or retain moisture (it is hygroscopic).

Maybe this is the Solution. If so, this is just exactly what my Crispy Critter (the solder-tip-cleaning-sponge) needs, I soaked the sponge in PG. So far, it seems to stay moist much longer, and it readily accepts more water (or more PG).

More (or longer) observation is clearly needed, and I will post an update later.

Wednesday, August 24, 2011

The difference between Life and Death is a very thin fragile Line, that most of us will cross but only once. The lives left on this side of a Passing, will be undoubtedly be forever changed.

Yesterday, I learned of the unexpected death of the young Wife of a young web Friend. I have never met either him or her. I know them only by his Blog and a few e-mail exchanges, but I feel like they are Family.

Must of the time the Internet provides us with news and enjoyment. But, sometimes it provides us with unexpected heart ache.

Tuesday, August 23, 2011

In Febuary 2011, I posted a Blog Entry describing my dissatisfaction with Mouser's Component Bag Labels. After a while, the labels would fade, making my component bins of sorted SMT parts almost worthless.

They have change their paper and print process, and therefore the Component Bag Labels should now be much more fade resistant.

Thanks Mouser, for taking this concern seriously, and for the attention to details!

Here is Mouser's Responce and our e-mail exchange:

Hello Mr. Brown -

This is Mike ****** ** ******** and I work for Mouser Electronics. I read with interest your blog entry at http://wa0uwh.blogspot.com/2011/02/mouser-label-fades.html. In the time since you wrote the blog entry we’ve changed the paper we use and eliminated the thermal paper. If you’ve placed an order lately, have you noticed an improvement in the longevity of the print?

Thank you,

Mike

----------------------------

Mr Mike ******** -

This is wonderful news; Mouser Component Package Labels are now moreFade Resistant.

Can I share your e-mail with my Blog readers as an UPDATE?

I just re-looked at the component tags from my July 28 order. which Ihad already re-labeled with a black marker. The paper and label printdoes seem different.

Is the new print technology used at all shipping depots?

Again, Thanks, I am very happy that Mouser took this concern serious.

Regards,Eldon Brown

----------------------------

Mr. Brown I am very glad to hear that the printing is working better for you. This is the print technology we use for all of our shipments. You may share my email, though I request that you please remove my contact information (email and phone) so that I don't inadvertently get spammed if Google carries the page to the far ends of the earth.

There are several video on YouTube showing how to create stannous chloride with diluted acid and a current flow. Because it is stinky/messy and I am not ready to try that, I thought I would just try to dissolve the Tin in concentrated acid and then dilute as needed later.

So far I have dissolved 1 and 1/2 sinkers to nothing (the acid is still a clear liquid), the next sinker was added tonight.

The questions for a Chemist is:

How much Tin will a milliliter of HCL 34% acid absorb?

Does it become Stannous Chloride?

What are the other by products?

Please verify, the weight of the results should be the weight of the acid, plus the Tin, minus evaporation?

Does any of the Tin or Tin compound leave in the form of vapor?

My current plan is to continue adding Tin until it is no longer is absorb, and then the plating experiments begin.

Something that would allow a user to safely arm the fire control circuit, and maybe provide some DRAMATIC sound effects.

Maybe something like the sound of a cheap camera charging it's flash. It would be fun, and this would also alert by-standers, and Tess to be ready for retrieval.

I am thinking, For Arming Fire Control

From Idle

Quick push and release

Up Ramping Tone, followed by push, 3 second hold and Release

Med Tone, One second delay, flashing Blue LED

High Tone, Fire on next Release if within 3 seconds, flashing Red LED, Else ABORT

Down Ramping Tone

Return to Idle

To Change Valve Open Time

From Idle

Push, hold for 4 seconds

Report CW "P" (for Program Mode)

Quick push and release, with "boo-bonk" sound report for down

Two Quick push and release, with "boo-bink" sound report for up

Repeat two above, unless timeout

Report via CW "R" sound

Return to Idle

To Reset (ie reboot)

From Idle

Push and hold for 6 seconds

Report via CW "R" sound

Return to Idle

This style of human interface is used by the K1EL CW Keyer, which I find very usable. To provide tones and switch monitoring at the same time may require interrupt programming. A low idle power processor would avoid the need for a power switch.

The Valve Open Time would avoid un-necessarily expelling air after the Tennis Ball has left the barrel, which would be useful (but maybe a little dangerous when reloading?).

This would take very little SMT hardware and could be made on a very small PCB:

A user interface push button switch

Processor

A Small Piezo Speaker

Maybe an LED or two

A FET and/or Relay to drive the Air Valve

A few Headers for the 9 Volt Battery, Valve Connection and maybe a JTAG

The circuit board can be created quickly with the Toner Transfer Method as used by my other project.

Now all I need is to find a low drain power processor, and re-learn my programming skills,

Or, maybe someone would want to help?

UPDATE
Experiments today shows that I can save about 1/2 of the air charge by limiting the air valve open time to just that which is needed to shoot the ball from the barrel. But, this also may imply that there are some restrictions within the system; maybe the Valve, the bottle necks or the pipe size.

The first few low pressure test shots in the Shop scared Tess (my Dog) to death, it sounds like a fog horn. But later outside shots, where the sound did not reverberate, and where there was a ball to chase became great fun for her. Although Tess has not yet learned to look up, to see the ball fly, she usually waits for the first bounce, and then she is all over it!

Jury-Rigged Switch and Battery

The first few outside shots were at low pressure and with an un-weighted ball. It became clear after the first few shots that I need to hook-up the electric solenoid to a switch, instead of just using loose wires connected to a 9 Volt Battery. I jury-rigged a switch and battery with tape to the launcher.

Now it was time to try some high pressure shots.

The first high pressure shots were at 10, 20, 30, 40, 50 and then 60 pounds, with an un-weighted ball. Tess retrieved each with pleasure.

Most web Tennis Ball Launcher users weight the ball by inserting 16 pennies (via a cut slit). Tess could not figure out what I was doing to her ball, and then she found it strange, it rattled when carried or rolled. We played catch with the weighted ball for a few minutes, and now thinks it is normal. I also threaded a cable tie through two holes (across the penny slit) for tying a streamer and later a fishing line.

So now, for the first weighted shot; A Tennis Ball, containing 16 pennies, a 3 foot red marking tape streamer, and at 60 pounds of pressure.

When shot almost straight up, the weighted ball when above the top of a tree in the drive next to the Shop.

Now, how high was that?

I am not very good at estimating height (and, I do not have a sextant or barometer to drop :-).

But, I do have a Cell Phone, with an APP, . . . a Level with voice output. Moving away from the tree and sighting along the edge of the phone to the top of the tree, until the level spoke the words for 45 degrees, I can now measure the distance to the tree and add 6 feet for my eye level. The tree was 40 large paces away, plus 6 feet, implies the tree is 40 x 3 + 6 = about 126 feet.

My first full pressure, weighted ball, shot went up about 126 feet !!!!!

An attached fishing line may reduce the performance (the bow fish reel still on order).

For several more shots (and until it got dark) Tess was have as much fun as I, shooting this thing.

There were several things noticed that may need refinement:

A lot of air comes out after the ball has left the chamber, which implies that the valve may be restricting the flow, maybe a double value is necessary? Or, maybe the current 26 inch barrel needs to be longer?

The trigger switch worked well, but it seems un-safe. I initially considered a inline safety toggle switch and I may still install one.

First I had to build an Soft Drink to PVC adapter, most of the similar documented build use threaded inserts that are glued together to make this adapter. But with a lathe, the task was easy to convert an existing 1 inch to 1/2 inch slip adapter to the required threaded configuration.

While looking at a soft drink bottle, it appears the threaded area already has a place for an o-ring, so all that is needed is a thread and an o-ring landing.

The results may provide a stealthy leak proof adapter, note this has not been tested yet. Details will follow.

Original and as Modified

In case someone asks, a 1 liter soft drink bottle has 8 thread per inch, I don't think it is Metric, but it is hard to determine on such a short thread length.

Most documented builds use existing plumbing fittings as they are purchased, and there is no reason not. But for my build I decided to change the shape of the main fitting to be more pleasing to the eye.

Parts As Purchased

The main fitting connection to the barrel is with a coupler and adapter, or a modified cap and adapter, as used by the Triitent Pneumatic Launcher.

For my build, I modified the fittings as shown.

As ModifiedNot much was done to the Coupler

As will be used

The preliminary dry fit shows how it all should look when (almost) completed.

Dry FitThe Trigger, Third Bottle and Barrel to be Added

Note: I have not finished drinking the content of the third bottle, yet, . . burp :-)

The Trigger method has not be solidified yet, most documented Launchers use a standard electric underground sprinkler valves, modified for direct Pneumatic action.

This should be a very light Launcher, and maybe used over the shoulder for best aiming. This will be fun to shoot and use. Tess (my Dog) retrieval will make it just that much more enjoyable.

Monday, August 15, 2011

For the last few days I have been searching and collecting the parts to build a Tennis Ball Launcher, the goal is to Launch lines over the trees around my Shop for several Dipoles.

Previously I had collected Pulleys and Lag Bolts with plans to hire a tree climber to install the supports for an antennas.

Rod Ready to Fire

But, during Salmoncon (see previous post), Rod - KE7X showed me how easy it is to put lines over very-very tall trees for supports, using a Tennis Ball Launcher. In fact, the Tennis Ball Launched line can be put higher into a tree than possible with a tree climber.

The first problem is finding right size Launch Tube, a Tennis Ball is about 2.65 inches in diameter. Standard 2.5 inch Schedule 40 PVC pipe is about (as you might expect) 2.5 inches inside diameter. A Tennis Ball can be forced into this tube, with a ram of some sort. Many designs found on the web use this commonly available size PVC pipe (with a ram), and apparently they work quite well.

But, Rod (and other web users) suggest it is worth finding a length of lesser-available "2.5 inch SDR-21 PVC Pipe", a Tennis Ball fits fuzz tight in this slightly thinner wall pipe. The fittings for this size are readily available as they are are the same as used for normal Schedule 40 PVC pipe. Although 2.5 inch pipe and 2.5 inch fittings are not available at the standard Box Hardware Stores (Lowes).

With a little Googling, I found a local Whole Sale Plumbing Supply house that stocked 2.5 inch SDR-21 pipe in 20 foot lengths, and the price was not bad, at $22.00 per stick. They also had the fittings. I will add a parts list here (that I will use) later.

The next task was to find a valve, the larger the better, but at a reasonable price. There are several types and vendors available from the Box Hardware Stores. The valves are typically used for under ground sprinklers which are power and controlled by a timer. I wanted at least a 1 inch valve. Most newer Launcher designs seem to use one of this size. Rod's design (and other web users) uses two valves in parallel for more air flow, I may try two valves later. Some of the available values are complex and are overkill for a simple launcher. I found a simple One Inch Orbit Valve (#57101) for $12.00, we will see how well it performs.

The next task is to decide on the fill connection, pressure gauge, and release trigger mechanism. The fill connection and Pressure Gauge were found at an Auto Parts store, the gauge is a little bigger then I want but it will do.

For initial trials, I will use the standard electrical connection to the valve for the release. Rob, and most web users modify the valve to allow for simple pneumatic release and therefore not requiring a battery. The valve I purchased appears to operate correctly with just a 9 Volt battery, and yet it is simple enough that can be modified for pneumatic release if necessary.

Most published designs use a PVC pipe with caps for the air reservoir, I found one design, The Trident, that uses plastic coke bottles, which make the Launcher much lighter. I think my initial design I will try this approach. I am drinking the content of the first bottle as I write.

Wednesday, August 3, 2011

A Homebrew_PCB Yahoo Group User; DJ, suggested that I try to fix my flawed 10 mil Spirals as reported on my previous post. With the aid of a 15 power Microscope I was able to fix each of the "opens". A few flaws were hard to find, but tracing them around-and-around with an Ohm Meter under the Microscope did the trick.

Fixing the trace breaks was a job for very sharp soldering iron and a steady hand. Building a solder bridge at this scale is an interesting process.

The Flaw Fixed with a Solder Bridge
Click Image to Enlarge

The above photo show a typical solder bridge fix. The Tee Pin is included as a pointer and for scale.

Solder Bridge

When all flaws were fixed, each of the trace resistance was measured end-to-end and then between traces:

First Trace = 23.4 ohms

Second Trace = 23.3 ohms

Trace to Trace = multi-meg ohms

The Challenge suggests the resistance should be 18.0 ohms per trace.

While investigating the Double Spiral Challenge, it seemed like my traces were smaller than proposed by the Challenge. But, I did not have anything to verify my PCB Toner Transfer Method fabrication results.

Until, I thought of including a calibrated scale inside of the photos. But alas, I do not have a small calibrated scale, so I decided to use a coin, but it was far to big. Then I hit upon the idea of using an Standard SMD part. The following photo contains a Standard 0805 SMD Resistor, from it a scale can be calibrated and distance measured.

Looking at the circuit board at this Magnified scale you wonder how any electronic device could possible work, with all of its flaws.

I may need to think about this more (later, it is very late at night) and now my thinking is dull. An update will follow.

The Tee Pin, Solder Bridge and the 0805 SMD Resistor

A Side Note: While futzing with my Cell Phone Camera and the add-on Attachment Lens (which was used to take these photos), I inadvertently twisted the Lens into two parts. With only the Lens base part attached, the Lens becomes a much higher power Macro Lens. Hum, . . I wonder why I did not know that before.

UPDATE

I received the following email from DJ, the owner/keeper of the Challenge, via the Homebrew_PCB Yahoo Group, it is included here for completeness.

Sweet!

Here's a tip: you know the track-to-track spacing is 20 mil (you did say 10/10 pattern, yes?). Given that, you can calculate the actual DPI of the photo (about 4300 dpi for the spot I was measuring). Also measure a track, and you can compute the actual track width (about 9.2 mil in some spots, 7.1 in others).

But simply measuring pixels-of-copper vs pixels-of-space should tell you how close to "perfect" you are.

Your ohms are a little high, some things that might cause that:

pinholes cause "necks" in the copper which add resistance

cleaning/scraping/sanding the copper might thin it somewhat

thinner traces on average would increase it

If you just go by the ohms ratio, it says your average trace width is 18/23 * 10 = 7.8 mil, which sounds close enough.

Did you measure the high ohms between the two tracks?

Also, if you have a flatbed scanner, they're often useful for high-accuracy PCB scans.

Tuesday, August 2, 2011

I have been making a lot of Homebrew PCB lately, using the Toner Transfer Method. Must of the boards are prototypes, which will be later be fabricated by one of the online PCB suppliers. I have been feeling very good about the Homebrew Process and have created several small boards with high resolution for very dense SMD projects. The highest resolution projects are 6 mil traces with 10 mil separations between traces or ground plane. My more typical project are created with 15 mil traces and 12 mil separations. Some of the details of these projects have been posted in my previous blogs (note: the selection will include a copy of this post).

The Spiral Challenge

Several years ago, when I first started Homebrewing PCB via the Toner Transfer Method, my resolutions and yield - was Horrible!

I saw the Homebrew_PCBs Yahoo Group Double Spiral Challenge web page, that provided the art work for process challenge, with several standard width traces and spacing. The image is used to produce two concentric PCB trace spirals, where the acceptable resistance between and end-to-end specifications are given.

In my early days of trying to make PCB, I could only hope for something that actually worked, regardless of the asthetics or (then low) resolution.

Now that I can produce High Resolution Homebrew Printed Circuit Boards almost 100% of the time, I decided to take the Yahoo Group Double Spiral Challenge. I selected the (mid range) "spiral-10mil" Challenge as a starting point. It is 10 mil traces with 10 mil spacing. A quick calculation, suggests that each spiral is about 200 inches (16 feet) long.

Currently, I use a Brother 1200dpi Laser printer (I know, most Toner Transfer users suggest it can not be used). A modified GBC Laminator and Pulsar Transfer Paper. See previous posts and my Salmoncon Take-Away-Notes.

My first attempt to Transfer an Toner Image, was flawed, a small hair or fuzz was trapped between the transfer paper and the PCB material. That is no real problem, I just re-scrub, reprint and to try again.

My Initial Results

On the second attempt, the Transferred Image looked promising, but the process had it's share of problems, I must have been just too anxious for the results.

The first thing that I forgot in the process, was to tape over the back side, to avoid unnecessarily etching of the extra copper. The process took much more time and Ferric Chloride than I expected. I thought this could be a problem.

From my previous Homebrew PCB build process, I know that the faster the etch and the smaller the copper area to be etched, creates the best results. This etch was taking to long!

The results, . . . . FAILURE !

The flaw is on the forth traceabove the ink spot

Resistance between traces implied there were NO shorts. But, end-to-end of each spiral was open. Under close Microscope inspection (and a with considerable amount of time), one spiral was found to be open in one spot, and the other was open in three spots. The one spiral is open on the forth trace, just above the ink dot on the photo.

All of the open flaws appear to be the results of etching through toner pin holes or single point under cutting. The opens did not appear to be the results of general narrowing of the traces. Each opens spot was shorter than the traces width themselves.

I will take the Challenge again, maybe even at a high resolution, but I will pay much more attentions to the details.